Monomeric emulsion stabilizers

ABSTRACT

A NOVEL CLASS OF MONOMERIC EMULSION STABILIZERS CONSISTS OF CERTAIN TYPES OF ETHYLENICALLY-UNSATURATED RADICALS COVALENTLY LINKED TO A QUATERNARY NITROGEN ATOM WHICH IN TURN IS COVALENTLY LINKED TO A LIPOPHILIC RADICAL. SUCH MONOMERS WILL POLYMERIZE WITH OTHER ETHYLENICALLY-UNSATURATED RADICALS FORMING SELF-STABILIZED, SURFACTANT-FREE POLYMERIC DISPERSIONS.

United States Patent 3,780,092 MONOMERIC EMULSION STABILIZERS Carlos M.Samour, Wellesley Hills, and Mildred C. Richards, Wakefield, Mass.,assignors to The Kendall Company, Walpole, Mass. No Drawing. Filed Oct.20, 1969, Ser. No. 867,899 Int. Cl. C07c 101/12, 101/16, 101/20 US. Cl.260-482 R 3 Claims ABSTRACT OF THE DISCLOSURE This invention relates tostabilizing agents for emulsion polymerization. More particularly itrelates to a class of quaternized organic salts which servesimultaneously as stabilizing agents for emulsion polymerizations and asmonomeric reactants in the polymerization, so that the salts become anintegral part of the polymer, which is thereby self-stabilized withoutthe use of surfactants.

Polymeric latices, derived from ethylenically-unsaturated monomers, arewidely used for a variety of applications, such as adhesive masses andbinders for nonwoven fabrics. Most conventional polymeric latices areproduced by an emulsion polymerization process, in which monomericmaterials are polymerized while they are dispersed in an aqueous mediumby means of a surface active agent. The surface active agent may beanionic in nature, such as soap or sodium lauryl sulfate. Alternatively,it may be of nonionic type as represented by various ethylene oxidederivatives, or by polyhydro-xy compounds, or it may be cationic, asrepresented by alkyl ammonium halides. Cationic agents are preferablycombined with a nonionic agent for improved performance. Thepolymerization of monomeric materials is also frequently effected in thepresence of water-soluble protective colloids or stabilizing agents. Anyof the above emulsifying or stabilizing agents leads to the presence ofa water-sensitive ingredient in the final polymeric latex. For latexutilizations wherein wet strength and resistance to the influence ofWater are desirable, as in most paper coatings, nonwoven fabrics,certain pressure-sensitive adhesive tapes, and the like, the presence ofa water-sensitive ingredient in the polymeric mass is undesirable.

A preferred method of avoiding the presence of Watersensitive elementsin a polymeric latex is to employ what is termed herein monomericemulsion stabilizersthat is, a class of organic monomer whichco-polymerize with the ethylenically-unsaturated monomers, becoming apart of the final polymer, but which stabilize the polymerizationprocess against the formation of coagulum and against subsequent phaseseparation. Such monomeric emulsion stabilizers may becationically-charged nitrogen compounds as set forth in my US. Pat. No.3,399,159 wherein the use of monomers such as vinyl pyridines,acidamines, and certain nitrogen-containing acrylic derivatives isdescribed.

AlsO, in my copending application Ser. No. 769,355, filed Oct. 21, 1968,now abandoned, there is described a process for preparing monomericemulsion stabilizers containing a quaternized nitrogen atom ionicallylinked to an acidic group, such as a sulfate, sulfite, sulfonate, orphosphate, which acid group is covalently bonded to a lipophilic groupof 8 to 24 carbon atoms.

3,780,092 Patented Dec. 18, 1973 It is an object of the presentinvention to prepare a new and useful class of monomeric emulsionstabilizers containing a quaternized nitrogen atom covalently linked toan ethylenically-unsaturated radical and to a lipophilic group, andionically linked to an anionic group.

It is a further object of the invention to prepare a new and usefulspecies of self-stabilized, surfactant-free polymeric emulsion suitablefor use as coatings, binding agents for nonwoven fabrics, adhesives, andthe like. Other objects of the invention will be apparent from thefollowing specification and claims.

It has now been found that the polymerization ofethylenically-unsaturated monomers may be advantageously carried out ifa major portion of such a monomer or mixture of monomers iscopolymerized with a minor proportion of a quaternized monomer of thegeneral formula:

R2 3 where V is an ethylenically-unsaturated radical selected from thefollowing three classes:

(a) Acid ester groups or acid amido groups derived from the dicarboxylicunsaturated acids maleic, fumaric, citraconic, or itaconic, such as HO-C0-CHz-(lJ-C O 0-, and HO-C OCHa-C 51-0 0 NH- H3 H! (b) Acrylic ester oracrylamido groups represented by the formulas CH =CR COO- and CH =CR--CONH where R, is H or CH (0) Allyl, CH =CHCH methallyl,

CH =C(CH )CH vinyloxy, CH =CHO; allyloxy,

CH =CHCH -O methallyloxy; CH =C(CH )CH O; vinyl acetoxy, CH =CHOCOCHallyl acetoxy;

CH =CHCH O'CO-CH and methallyl acetoxy,

CH =C(CH )CH OCOCH In the formula given above, the A moiety of themonomeric emulsion stabilizer is zero when V is allyl, methallyl, vinylacetoxy, allyl acetoxy, or methallyl acetoxy. Otherwise, A is a divalentradical selected from the classes consisting of (a) Ethylene, CH CHpropylene,

-CH CH -CH hydroxypropylene, CH -CHOH-CH acetoxypropylene,

and isopropylene, CH CH(CH ethylene, propylene, isopropylene, andhydroxypropylene being preferred; (b) OCH -CHR (OCH CHR where n equalszero to four and R again is H or CH The quaternary nitrogen group -N .R.R .R contains a lipophilic radical R By the term lipophilic radical inthe dams and specification herein is meant a radical containing analiphatic hydrocarbon chain having from about 7 to 28 carbon atoms, witha chain of 9 to 18 carbon atoms preferred. This hydrocarbon group may becovalently linked to the nitrogen either directly or through one of thefollowing intermediate linkages: a benzyl group; an ester group such asCH CH OCO-R a polyalkylene oxide group such as O--CH CHR (OCH -CHR )n-ORwhere R; is H or CH; and n is to 4; an alkyl acetoxy or alkyl acetamidogroup such as CH -COOR and -CH --CONHR alkyl alkylene ethers such as -CHOR and alkyl amides such as -CH CH(CH )NHCO-R The lipophilic radical Rmay be linear or branched, saturated or unsaturated.

In the preferred embodiments of the invention, R is an alkyl or benzylgroup of from 1 to 7 carbon atoms, and R is either an alkyl or benzylgroup of from 1 to 7 carbon atoms or a group selected from the classconsisting of R -0-COCH and R NH-COCH where R is H or an alkyl group offrom 1 to 4 carbon atoms. Cases Where R and R are lower alkyl groups,especially methyl groups, are preferred.

R and R may also be valence bonds of a cyclic amine of the piperidine ormorpholine type,

RI Ba J In the monomeric emulsion stabilizers of this invention, the Xwhich is ionically linked to the quaternary nitrogen is an acid radicalselected from the class consisting of F-, Cl-, Br, I", CH SO C H SO andwith C1", Br", or CH SO preferred.

Typical reaction procedures for producing the monomeric emulsionstabilizers of this invention include the reaction of an appropriateethylenically-unsaturated alkylene halide with a tertiary aminecontaining a lipophilic group or with an appropriate ring compound inwhich nitrogen is a ring member: or the reaction of a halogenatedcompound containing active halogen with an ethylenicallyunsaturatedcompound containing a tertiary amine.

Representative preparations are the reactions between allyl chloride anddimethyl dodecyl amine or dimethyl hexadecyl amine; between allylbromide and N-cocomorpholine, in which the nitrogen atom in themorpholine ring is covalently bonded to a mixture of saturated alkylgroups averaging 12 carbon atoms; between dimethyl allyl amine anddodecyl chloroacetate; and between maleic anhydride and the reactionproduct of dimethylamino ethanol and lauryl bromide. Specificillustrations of these and other reactions Will be given below in thefollowing examples, together with illustrations of their use asmonomeric emulsion stabilizers.

EXAMPLE 1 Preparation and use of allyl dodecyl dimethyl ammoniumchloride 23 grams of dimethyl dodecyl amine were dissolved in 31 gramsof H 0 and 9 grams of allyl chloride were added. After 6 hours stirringat 25 C. some precipitation had occurred. 50 grams more H O were addedand stirring was continued for 16 hours, resulting in a slightly cloudyhomogenous solution.

18 grams of this solution were dissolved in 290 grams of H 0, and 100grams of ethyl acrylate were emulsified therein by gradual addition withstirring. The pH of the emulsion was about 6.0. It was cooled to 17 C.and 0.3 gram of 3% H 0 in H O were added, followed by the dropwiseaddition of a reductant solution (0.02 gram of ferrous ammonium sulfateand 0.5 gram of ascorbic acid in grams of H 0). A nitrogen atmospherewas maintained throughout the polymerization in all examples,

polymerization being initiated in the present instance after 1.8 gramsof reductant solution had been added. The exotherm was 33 C. in abouttwo minutes. Addition of 2 grams more reductant and 2 grams more of 3% H0 after the reaction had cooled gave a 5 C. exotherm. The yield ofpolymer formed was over 90% of theoretical, and no coagulum was formed.

Essentially similar results were obtained when the ethyl acrylate wasreplaced by a mixture of 10 parts of ethyl acrylate and 74 parts of2-ethylhexyl acrylate. The above procedure was also repeated usingdimethyl hexadecyl amine in place of dimethyl dodecyl amine, and using amixture of 20 grams of vinyl acetate and grams of 2- ethylhexyl acrylateas the principal monomer.

EXAMPLE 2 Preparation and use of vinyloxyethyl dimethyltridecyloxycarbonylmethyl ammonium chloride 28.8 grams ofdimethylaminoethyl vinyl ether were dissolved in 98 grams ofacrylonitrile. After cooling the solution to 15 C., 69.3 grams oftridecylchloroacetate were added with stirring. Stirring was continuedfor 72 hours at 25 C. Analysis showed 100% conversion to the quaternizedammonium chloride.

6 grams of the above solution were dissolved in 280 grams of H 0, towhich was added with stirring a mixture of 80 grams of ethyl acrylate,10 grams of butyl acrylate, and 7 grams of acrylonitrile. The pH of theresulting emulsion was between 5.0 and 5.5. The emulsion was cooled to17 C., after which polymerization was initiated and maintained using H 0and reductant as in Example 1. There was no coagulum formed in theresulting polymeric emulsion, and the yield was 92% of theoretical.

EXAMPLE 3 Preparation and use of methacryloyloxyethyl dimethyldodecyloxycarbonylmethyl ammonium chloride 15.9 grams ofdimethylaminoethyl methacrylate and 26.6 grams of dodecyl chloroacetatewere stirred together in 45 grams of ethyl acetate at room temperature.After a short period of stirring, the white crystalline solid quaternaryammonium compound was formed, and was isolated.

3.0 grams of the above quaternary compound were dissolved in 350 gramsof H 0, to which a mixture of 10 grams of ethyl acrylate and 73.6 gramsof 2-ethylhexy1 acrylate were added with stirring. The pH of theresulting emulsion was 6.0. It was cooled to 18 C., and polymerizationwas initiated and maintained as in the above examples. The polymer yieldwas about If the proper equivalents of dimethylaminoethyl methacrylateand tridecylchloroacetate are used to form the quaternized compound, theresulting methacryloyloxy ethyl dimethyl tridecyloxycarbonylmethylammonium chloride acts as a monomeric emulsion stabilizer similar to itsdodecyl homolog.

EXAMPLE 4 Preparation and use of allyloxycarbonylmethyl dimethylhexadecyl ammonium chloride 13.5 grams of allyl chloroacetaoe were addedwith stirring to 26.9 grams of dimethyl hexadecyl amine in 40 grams ofdimethyl formamide. Two layers were initially formed, but with continuedstirring for 1-6 hours at 25 C., a clear, light yellow homogeneoussolution was obtained. After 6 days standing, the solvent was removedunder vacuum at 40 C. The resultant solid was washed with ethyl etherand dried. The product was somewhat greasy, and analysis showed 97% ofthe theoretical chlo ride content present.

Using the same general procedures as in the above examples, a mixture of55 grams of vinyl acetate and 45 grams of butyl acrylate were emulsifiedusing 3% of the weight of the above monomeric emulsifying agent, based 5on the weight of vinyl acetate and butyl acrylate, dissolved in 280grams of H 0. Polymerization was initiated and maintained as above bythe use of H and reductant. The yield of polymer was 83%.

EXAMPLE 5 Preparation and use of allyl dodecylmorpholinium bromide 91.3grams of N-cocomorpholine and 45 grams of allyl bromide were stirred in306 grams of H 0 at 25 C. for 24 hours. The clear, colorless solutioncontained 96% of the theoretical yield of quaternized ammonium salt.

5 grams of the above 30% aqueous solution were dissolved in 1,000 gramsof H 0, and a mixture of 160 grams of ethyl acrylate, 20 grams ofacrylonitrile, and 20 grams of butyl acrylate were added with stirring.The resultant emulsion was polymerized by the use of 0.3 gram of tbutylperoxy maleic acid and 4.1 grams of the ferrous ammoniumsulfate-ascorbic acid reductant solution. The yield of polymer was 96%of theoretical.

EXAMPLE 6 Preparation and use of 3-(4-hydroxymaleoyl)-aminopropyldimethyl tridecyloxycarbonylmethyl ammonium chloride This quaternarycompound was prepared in two stages. 20.4 grams of dimethylaminopropylamino were mixed with 55.4 grams of tridecyl chloroacetate in 75.8grams of acrylonitrile. After 72 hours at 25 C., 90% of the theoreticalchloride content was found in the form of the quaternized salt. Thesolution was cooled and 19.6 grams of crushed maleic anhydride wereadded, cooling being employed to keep the exothermic reaction below 22C. 100% of the theoretical chloride ion was found by analysis.

6 grams of the above solution were dissolved in 280 grams of H 0, and amixture of 80- grams of ethyl acrylate, grams of butyl acrylate, and 7grams of acrylonitrile were added with stirring. The resulting emulsion,pH 4.0 to 4.5, was cooled, and polymerization was initiated andmaintained by the H O -reductant system described in Example 1. Lessthan 1% of coagulum was formed, and the yield of polymer was 92%.

EXAMPLE 7 Preparation and use of 2-(4-hydroxymaleoyloxy)ethyl dimethylp-dodecylbenzyl ammonium chloride The preparation of this quaternarycompound, like that of Example 6, was a two-stage reaction. 29.5 gramsof pdodecylbenzyl chloride and 8.9 grams of dimethylamino ethanol weremixed in 38.4 grams of acrylonitrile. After 24 hours at 25 C., 9.8 gramsof crushed maleic anhydride were added to the clear solution. After 13days standing, the separated crystalline compound was washed with ethylacetate and dried.

2.25 grams of the quaternary salt were dissolved in 290 grams of H 0 and75 grams of ethyl acrylate were added with stirring. The resultantemulsion was polymerized with the H O -reductant system used in previousexamples. The yield of polymer was 96% of theoretical.

When lauryl bromide was used in the initial quaternization reaction inplace of p-dodecyl'benzyl chloride, followed by reaction with maleicanhydride, 2-(4-hydroxymaleoyloxy)ethyldimethyl dodecyl ammonium bromidewas produced. Its behavior as a monomeric emulsion stabilizer in thepolymerization of ethyl acrylate was essentially similar to the behaviorof 2-(4-hydroxymaleoyloxy) ethyl dimethyl p-dodecylbenzyl ammoniumchloride.

EXAMPLE 8 Preparation and use of methacryloyloxyethyl dimethyl hexadecylammonium bromide 19.3 grams of 2-bromethyl methacrylate and 27.8 gramsof dimethyl hexadecylamine were mixed at 25 C.

6 in 47.1 grams of acrylonitrile. After 6 days, 92% of the theoreticalbromide was found in the form of the quaternized salt.

3 grams of the above solution diluted to 33% in acrylonitrile were addedto 280 grams of H 0. A mixture of grams of ethyl acrylate, 10 grams ofbutyl acrylate, and 8 grams of acrylonitrile were added with stirring.Polymerization of the resultant emulsion was initiated and maintained bythe H O -reductant system described in Example 1. The yield of polymerwas 96% EXAMPLE 9 Preparation and use of allyl dimethyltridecyloxycarbonylmethyl ammonium chloride 8.5 grams of dimethylallylamine and 27.7 grams of tridecyl chloroacetate were mixed togetherin 36 grams of dimethyl formamide at 25 C. After 15 days standing,petroleum ether was added to precipitate and isolate the crystallineproduct. Analysis showed that of the theoretical chloride content was inthe form of the quaternized salt.

5 grams of the quaternized compound were dissolved in 29 0 grams of H 0,and 100 grams of ethyl acrylate were added with stirring. The resultingemulsion was polymerized by the customary H O -reductant system. Theyield of usable polymer was over When 26.3 grams of dodecylchloroacetate was substituted for the 27.7 grams of the tridecylchloroacetate, the dodecyl homolog of the above-described monomericemulsion stabilizer was prepared. Its function and behavior are the sameas that of the tridecyl compound.

EXAMPLE 10 Preparation and use of vinyloxyethyl dimethyl p-dodecylbenzylammonium chloride 11.5 grams of dimethylaminoethyl vinyl ether and 29.5grams of p-dodecylbenzyl chloride were stirred together in 41 grams ofacrylonitrile at 25 C. for 24 hours. The chloride by analysis was foundto be completely quater nized.

2.5 grams of the above solution were dissolved in 700 grams of H 0. Amixture of 200 grams of ethyl acrylate, 25 grams of butylacrylate, and24 grams of acrylonitrile were added with stirring. The resultantemulsion was polymerized using a total of 35 grams of 3% H 0 and 11grams of the reductant solution of Example 1. No coagulum was formed,and the polymer yield was 91% of theoretical.

EXAMPLE 11 Preparation and use of S-methacryloyloxy 2-hydroxy propyldimethyl octadecyl methyl ammonium sulfate Equimolar quantities ofN-methyl-N-octadecyl amine and glycidyl methacrylate were reactedtogether in methanol to form methacryloyloxyhydroxypropyl methyloctadecyl amine. 14.3 grams of the resultant amine were dissolved in 20grams of dimethyl formamide and 4.2 grams of dimethyl sulfate were addedslowly with stirring. After 10 days standing at 25 C., 9 grams ofcrystalline material was isolated, washed with ether, and dried. Thesulfate band in the crystalline product was identified in the LR.

spectrum.

2.25 grams of the above stabilizer were dissolved in 290 grams of H 0.75 grams of ethyl acrylate were added with stirring. Polymerization wasinitiated and maintained by the usual H O -reductant system. Less than 1gram of coagulum formed, and the polymer yield was 96% of theoretical.

EXAMPLE 12 Preparation and use of allyl hexadecyl dimethyl ammoniumfluoride Allyl hexadecyl dimethyl ammonium chloride was prepared byreacting allyl chloride and dimethyl hexadecyl amine as set forth inExample 1. 17.8 grams of the chlo ride in 23.5% aqueous solution weretreated with a stoichiometric excess of AgF in aqueous solution untilanalysis of the filtrate showed only a trace of chloride ion present.Excess silver ion was removed by the careful addition of NaCl, AgClbeing removed by filtration.

64 grams of ethyl acrylate, 8 grams of butyl acrylate, and 8 grams ofacrylonitrile were emulsified by gradual addition with stirring to 2.4grams (3% by weight) of the allyl hexadecyl dimethyl ammonium fluoridein 120 grams of H 0. The pH of the emulsion was about 6.0. It was cooledto 20 C. and 10 grams of 3% aqueous H were added, followed by thedropwise addition of the reductant solution of Example 1 untilpolymerization was initiated after grams of reductant had been added.The exotherm was C. in 13 minutes. A total of 14 grams of reductant and13 grams of aqueous H 0 were used to complete the polymerization. Nocoagulum was formed and the polymer yield was 95 EXAMPLE 13 Preparationof allyl hexadecyl dimethyl ammonium iodide 16.8 grams of allyl iodidewere dissolved in 44.6 grams of ethyl acetate and 27.8 grams of dimethylhexadecyl amine were added slowly with stirring at room temperature.Within minutes after the addition of the amine was complete, theviscosity of the solution increased and crystallization occurred. After24 hours the crystals were filtered, washed with ethyl acetate, anddried. The colorless crystalline product contained 88% of thetheoretical amount of iodide ion.

The proportion by weight of monomeric emulsion stabilizer used tostabilize the polymerization of other ethylenically-unsaturated monomerswill depend on the nature of the latter. In general, 0.1% to 10% ofstabilizer is used, with a preferred range of 1% to 5%. In the casewhere ethyl acrylate is the major monomer, 0.5% of emulsion stabilizerwill generally result in a satisfactory polymerization. In the case ofZ-ethylhexyl acrylate, the amount of stabilizer is increased to from 3%to 5%.

Ethylenically-unsaturated monomers suitable for copolymerizing with themonomeric emulsion stabilizers of this invention comprise vinyl acetate,vinyl chloride, acrylonitrile, and acrylic monomers in generalrepresented by the general formula where R is a hydrogen atom or amethyl group, and R is a saturated alkyl radical of 1 to 14 carbonatoms. As is known in the art of preparing acrylic ester polymers, thesoftness of the polymer and the difliculty of initiating polymerizationincrease as the number of carbon atoms in the ester group increases. Inthe practice of this invention, when the acrylic monomer contains morethan 8 carbon atoms in the ester group, it is advantageous to mixtherewith at least about of an acrylic ester with fewer than 4 carbonatoms in the ester group to initiate polymerization and enhance thestability of the dispersion. Therefore, esters in which the ester groupcontains from 1 to 4 carbon atoms are preferred.

Mixtures of more than one such ethylenically-unsaturated monomer may beused, and in order to impart special properties of toughness, rigidity,or cross-linking reactivity to the polymer, a minor proportion, usuallyless than 20 mole percent, of the major monomer may be replaced by someother ethylenically-unsaturated monomer such as vinyl esters, typifiedby vinyl laurate and vinyl stearate; vinyl ethers such as vinyl methylether, vinyl ethyl ether, and vinyl butyl ether; di-unsaturated monomerssuch as diethylene glycol diacrylate, ethylene glycol diitaconate,diallyl phthalate, divinyl benzene and the like; acrylic and methacrylicacids, acrylamide and methacrylamide, hydroxyethyl acrylate andmethacrylate, and hydroxypropyl acrylate and methacrylate, and styrene.

Although the above examples using the stabilizers of this inventionrelate to batch processing, their use is equally well adapted tocontinuous polymerization processes.

Having thus described our invention we claim:

1. Compounds corresponding to the formula V is selected from the classconsisting of acryl or methacryl ester groups;

A is selected from the class consisting of ethylene, propylene,isopropylene, and hydroxypropylene groups; R and R are selected from theclass consisting of benzyl groups and alkyl groups of from 1 to 7 carbonatoms; R is a lipophilic saturated aliphatic hydrocarbon-oxycarbonylmethyl group containing at least one aliphatic hydrocarbon group of fromabout 7 to 28 carbon atoms; and X is a radical selected from the classconsisting of F",

01 I CH SOf', C2H5SO4 and 2. The compound according to claim 1 wherein Rand R are methyl groups.

3. Methacryloyloxyethyl dimethyl dodecyloxycarbonylmethyl ammoniumchloride.

References Cited UNITED STATES PATENTS 3,176,038 Zachry et a1. 260-485LORRAINE A. WEINBERGER, Primary Examiner P. J. KILLOS, AssistantExaminer US. Cl. X.R.

117161 UZ; 26029.6 TA, 29.6 HN, 29.6 SQ, 79.3 M, 80.73, 85.5 ES, 85.5AM, 86.1 N, 87.1, 247, 247.1, 247.2 A, 247.2 B, 293.73, 293.81, 293.85,293.86, 293.88, 401, 404, 404.5, 459, 485 H, 486H, 501.13, 501.15, 567.6M

